What sort of cam to stay within emissions?
Discussion
I'm looking to do a cam swap on my 5.7 LS1.
I've done this on older RV8's before, but my LS1 is new enough to need Cats and undergo the Basic Emissions Test come MoT time.
Just wondering what sort of impact or limit there is to running a hot cam and keeping the vehicle able to pass?
The car is a 1999 (not a Monaro
). And has cats, I'll be retaining the cats. I know some US states check for emissions, but I'm not sure what they check for. So I'm struggling to find much useful info out on US sites.
I know the UK MoT only checks for Carbon Monoxide and Hydrocarbons:
http://www.cammotion.com/camshafts/titan-3-ls3-cam...
Titan 3 LS3 Camshaft (227/237-113+3.5)
As it needs to work with stock heads, long tube exhaust manifolds and probably an LS6 style intake.
I'm not looking for outright power or a dyno queen. I'm more interested in changing the character of the engine to promote more mid and upper rev range performance. As this should suit the short gearing (6 speed manual and going to change to 4.10:1 final drive) and B road driving better.
I wouldn't object to a bit of lope at idle however.
Is such a cam likely to pass an MoT?
I've done this on older RV8's before, but my LS1 is new enough to need Cats and undergo the Basic Emissions Test come MoT time.
Just wondering what sort of impact or limit there is to running a hot cam and keeping the vehicle able to pass?
The car is a 1999 (not a Monaro
). And has cats, I'll be retaining the cats. I know some US states check for emissions, but I'm not sure what they check for. So I'm struggling to find much useful info out on US sites.I know the UK MoT only checks for Carbon Monoxide and Hydrocarbons:
dotGov said:
The first test consists of checking the emissions at ’fast-idle speed’ which involves running the engine at a speed of 2500 - 3000 rpm. During this test the emissions of CO and HC will be checked and a further check will be made on the lambda (1) value. The second test consists of a check of emissions at ‘normal idle speed’ in which the engine will idle between 450 and 1500rpm, but in this case only the CO emissions are assessed.
The emissions limits to be met are specified for both the fast and normal idle tests. At fast idle, CO must be at or less than 0.2%, HC at or less than 200 parts per million (ppm), and the lambda value(1) must be between 0.97 and 1.03. At normal idle, CO must be at or less than 0.3%
I've been recommended this cam:The emissions limits to be met are specified for both the fast and normal idle tests. At fast idle, CO must be at or less than 0.2%, HC at or less than 200 parts per million (ppm), and the lambda value(1) must be between 0.97 and 1.03. At normal idle, CO must be at or less than 0.3%
http://www.cammotion.com/camshafts/titan-3-ls3-cam...
Titan 3 LS3 Camshaft (227/237-113+3.5)
As it needs to work with stock heads, long tube exhaust manifolds and probably an LS6 style intake.
I'm not looking for outright power or a dyno queen. I'm more interested in changing the character of the engine to promote more mid and upper rev range performance. As this should suit the short gearing (6 speed manual and going to change to 4.10:1 final drive) and B road driving better.
I wouldn't object to a bit of lope at idle however.
Is such a cam likely to pass an MoT?
on my monaro 04 ls1 , it’s had headers sports cat intake done plus a re map , it is a battle to get it through an mot even when cats are hot on the standard ls1 cam , not saying it can’t be done but it’s on the limit of emissions any way from my understanding , vw maybe could advise lol
if you have 4.11 gears and you want emissions compliance, stick with the stock cam
. An ls6 cam could be an option, but probably wont gain enough to be worth it.
That cam wont even be close to passing an mot. And its for an ls3 not ls1 anyway.
. An ls6 cam could be an option, but probably wont gain enough to be worth it.
That cam wont even be close to passing an mot. And its for an ls3 not ls1 anyway.
Edited by fred bloggs on Wednesday 22 May 14:01
An easy check for emissions is to look at overlap, most cam specs are quoted for duration at a lift of 0.050", so the actual overlap is going to be greater than this, but it'll at least give you an idea as to whether you stand a chance...
Take the average of intake / exhaust, then subtract the LSA * 2.
So in that example, 227/237 with a 113 LSA, you've got:
(227 + 237) / 2 = 232
113 * 2 = 226
232 - 226 = 6
You want 0 or less overlap to even come close, 6* is not going to pass. It'll definitely chop nicely at idle though
As some context, 99ish LS1 OEM cam is 199/207 on a 117 (assuming http://www.jankyshack.com/gm-ls-cam-specs/ is correct, it'll be close anyway)
That's -31* of overlap. So +6* is... going to be a struggle unless yours 'cats' vent directly into an alternate dimension
Take the average of intake / exhaust, then subtract the LSA * 2.
So in that example, 227/237 with a 113 LSA, you've got:
(227 + 237) / 2 = 232
113 * 2 = 226
232 - 226 = 6
You want 0 or less overlap to even come close, 6* is not going to pass. It'll definitely chop nicely at idle though
As some context, 99ish LS1 OEM cam is 199/207 on a 117 (assuming http://www.jankyshack.com/gm-ls-cam-specs/ is correct, it'll be close anyway)
That's -31* of overlap. So +6* is... going to be a struggle unless yours 'cats' vent directly into an alternate dimension
ringram said:
220/224-114 is a good choice too. TFS do one of this spec. I think Comp have a 219/223 or similar as well.
If in doubt, listen to this man. Or wait for monkfish1 to wade in 
Ooo I've just had a thought, now that monkfish is no more, could we find out the specs of the various magic cams now?
Aitch H said:
I have my old 222/226-115+3 .6”/.6” EPS cam that always passed the MOT sitting in a box that would work with that spec if you’re interested. I swapped it out for a monkfish ‘magic 2’ cam
Ta. What sort of character would a cam like that have? And what sort of gains. Also how does it compare to the Monkfish cam? I guess my question is, why did you change it. But yes I could well be interested.
Are you able to post some pics at all? I assume it’s in good order. What sort of money do you want for it? Feel free to PM if you prefer
Well totally un-cam related, I installed a new quick shifter last night.
The stock shift was bugging me on the T56. I didn’t really mind the throw. I’m used to Land Rovers and farm tractors after all. But 2nd to 3rd was quite a challenge. Especially at speed, where it was all too easy to grab 5th instead of 3rd.
But my real worry was catching 1st when coming out of 2nd at WOT.
Bit of searching and I found a Hawks shifter in the US for decent money including shipping. Only took a week to get here too.
I also new there was a bit of an oil weep on the box, from when it was up on high lift. So thought I could investigate this.
After wrestling with the trim I managed to get to the old shifter. A completely shot gasket and the bolts retaining the shifter where all loose and only finger tight too!!
Not sure if there should be oil here. But this is definitely where the leak has been.
The shifter on the car was a blue anodised B&M branded one. Not sure if this is stock for a T56? It seemed odd the retaining screws where loose. But the fitment and shifter stick all looked stock.
|https://thumbsnap.com/wZZBFhex[/url]
The new Hawks branded shifter is much more substantial however and a lot chunkier and heavier.
[url]
Fitting the shifter was pretty straight forward. In fact took a lot less time that I spent messing with the centre console trim when getting the old shifter out
The new shifter also has adjustable stops which you set on 3rd and 4th gear.
The shift stick in the Hawks is much shorter and lighter being aluminium. Sorry no pic of the old one.
Rubber boot reinstalled and I refitted the stock leather gearknob replacing the white plasticky one someone had fitted. Sadly a previous owner broke the gaiter retaining ring. Looks like I can get a new one from the States for about £50!!!! Suspect it was broken when an aftermarket alarm was installed.
So what was the verdict?
Well I had a little trepidation. I fitted a quick shifter to my Impreza Turbo. And while that did reduce the throw it was notchy and hugely heavy. You wouldn’t believe how much force was required vs stock to select the gears.
Thankfully this is not the case here. The shift is smooth and no heavier than it was before. But my word, it is now a lovely feeling positive shift. No play or wobble at all in the stick. Just a nice positive feel.
The throw is noticeably less and precision has improved tenfold. This is certainly the best gearshift I’ve personally owned and certainly ranks up there as one of the better ones I’ve driven. I think it matches the Mk4 MX-5 I’ve driven and that had a sublime shifter.
2nd to 3rd is now easy and very nice, rather than a chore to achieve. When something can be improved so much. I makes you wonder how and why car makers let such substandard designs make it to production.
I assume aftermarket shifters are available for the manual Monaro’s. If so, wow what a transformation.
The stock shift was bugging me on the T56. I didn’t really mind the throw. I’m used to Land Rovers and farm tractors after all. But 2nd to 3rd was quite a challenge. Especially at speed, where it was all too easy to grab 5th instead of 3rd.
But my real worry was catching 1st when coming out of 2nd at WOT.
Bit of searching and I found a Hawks shifter in the US for decent money including shipping. Only took a week to get here too.
I also new there was a bit of an oil weep on the box, from when it was up on high lift. So thought I could investigate this.
After wrestling with the trim I managed to get to the old shifter. A completely shot gasket and the bolts retaining the shifter where all loose and only finger tight too!!
Not sure if there should be oil here. But this is definitely where the leak has been.
The shifter on the car was a blue anodised B&M branded one. Not sure if this is stock for a T56? It seemed odd the retaining screws where loose. But the fitment and shifter stick all looked stock.
|https://thumbsnap.com/wZZBFhex[/url]The new Hawks branded shifter is much more substantial however and a lot chunkier and heavier.
[url]Fitting the shifter was pretty straight forward. In fact took a lot less time that I spent messing with the centre console trim when getting the old shifter out
The new shifter also has adjustable stops which you set on 3rd and 4th gear.
The shift stick in the Hawks is much shorter and lighter being aluminium. Sorry no pic of the old one.
Rubber boot reinstalled and I refitted the stock leather gearknob replacing the white plasticky one someone had fitted. Sadly a previous owner broke the gaiter retaining ring. Looks like I can get a new one from the States for about £50!!!! Suspect it was broken when an aftermarket alarm was installed.
So what was the verdict?
Well I had a little trepidation. I fitted a quick shifter to my Impreza Turbo. And while that did reduce the throw it was notchy and hugely heavy. You wouldn’t believe how much force was required vs stock to select the gears.
Thankfully this is not the case here. The shift is smooth and no heavier than it was before. But my word, it is now a lovely feeling positive shift. No play or wobble at all in the stick. Just a nice positive feel.
The throw is noticeably less and precision has improved tenfold. This is certainly the best gearshift I’ve personally owned and certainly ranks up there as one of the better ones I’ve driven. I think it matches the Mk4 MX-5 I’ve driven and that had a sublime shifter.
2nd to 3rd is now easy and very nice, rather than a chore to achieve. When something can be improved so much. I makes you wonder how and why car makers let such substandard designs make it to production.
I assume aftermarket shifters are available for the manual Monaro’s. If so, wow what a transformation.
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